Electbic igniter



March 12, 1929. w, J ROBB 1,704,763

ELECTRIC IGNITER Filed Marph 20, 1926 I N VEN TOR.

ATTORNEYS,

Patented Mar. 12, 1929.

WILLIAM 3'. R033, OF MILWAUKEE, WISCONSIN.

ELECTRIC IGNITER.

Application filed March 20, 1926.- Serial Nb. 96,389. 7

My invention relates to improvements in electrical ignition systems for internal combustion engines, with particular reference tothe means for breaking the primary circuit of the high tension coil in a manner to most ettectively ignite the combustible gases in the respective cylinders.

The object of this invention is to provide improved means for obtaining a double ignition within each cylinder through the development of two impulses or waves in the secondary circuit of the coil in such quick succession as to accelerate combustion in the cylinder insure the ignition of the gases therein it, for any reason, the electric are initially produced fails to ignite such gases.

further object of my invention is to provide an electrical ignition system having a high tension coil, with means, associated with a circuit breaker for developing an initial impulse or wave of ordinary intensity in the secondary circuit, followed by a second impulse or wave of effective intensity which is caused by a second interruption of the primarycircuit.

In the'drawings v7 is a view of a circuit breaking aptrical circuits, including the battery, high ten sion coil, condenser, distributor and spark plug being illustrated conventionally.

Figure 2 is a view of a circuit breaker, embodying a modified form of construction.

in Figure 1, a timer cam 5 of the ordinary type, associated with the distributor of an ignition apparatus, is illustrated in its usual relation to a circuit breaking lever 6 having a contact point 7 adapted for registry with a relatively stationary contact point 8 carried by the frame or casing and electrically connected by the lead 9 with the primary winding 10 oil a transformer or high tension coil of ordinary construction, the other end of the winding 10 being connected by the lead 11 with a source of electrical energy, such as the battery l2. A condenser 13 is bridged across the windin 10 in the ordinary manner, and the secondary winding 14 has one end grounded and the other end connected through the distributor 15 With the spark plugs, one of which is indicated at 16. The circuit breaker lever 6 is normally urged by a spring 18 in a direction to carry its contact 7 to circuit closing position on contact 8, in which position it remains except when swung to circuit breaking posltionhby the action of the timer cam 5.

All of the above mentioned parts may be of ordinary construction and no further description is deemed necessary.

It will be observed, however, that the circuit breaker lever 6 is provided with two actuating arms 20 and 21 adapted to transmit motion to the lever from the cam 5 to actuate said lever against the spring tension and break the primary circuit by separating contacts 7 and 8. The arms 20 and 21 are insulated or composed of insulating material and they are so formed that when the timer cam is rotated in the direction indicated by the arrow, its high points 5, 5 5, 5 5 and 5 will each engage the arms 20 and 21 in succession and lift the lever 6 to circuit breaking position. The arm 1'21 is so spaced from the arm 20 as to allow lever 6 to retract and close the circuit through the contacts?' and 8 when the associated high point on the cam is substantially midway between these two arms. The'arms are preferably located on the opposite side of a perpendicular line from the lever through the axis of cam rotation from that side on which the pivot pin 25 is located. This is done in order to avoid the snubbing effect and consequent accelerated wear which would paratus embodying my invent1on,the elecotherwise occur on the ends of the arms 20 and 21. Therefore, the arm 21 is made longer than the arm 20 in order each may transfer substantially equal movement to the lever 6.

ing its discharge. And it tor. any reason due to carbon on the spark points, or to an improper mixture, or to a weak battery, the first arcshould fail to ignite the combustible mixture, the production of the second arc will greatly increase the probability of ignition, either because of the intensification of the are or because of the heating of the points and v- ,vaporization of some of tlfi hydrocarbon particles. V

The principle of operation is quite different from that in which the primary circuit is broken by a vibrator of ordinary type. With my improved-construction, the separation of the contact points 7 and 8 is timed and the interval is sulficient to allow the current to be fully reestablished in the primary circuit and to reverse in the secondary, whereas in the use of'the ordinary vibrator-the breaks in the primary circuit occur too rapidly to allow a completion of the wave cycle. The ordinary vibrator tends to flatten out the current Waves in the secondary, WVhile it is possible that a vibrator might be so organized as to break the primary circuit successively in timed relation to the wave cycles in the secondary, I am not aware of a vibrator which has been designed to accomplish any such rcsult.

It-is of course essential to my invention that both operations of the circuit breaker, for any given spark plug 16, shall take place Within the igniting interval of the particular Cylinder with which that spark plug is associated, whereby the same charge may be ignited twice under proper conditions in time for the development of maximum power. The first ignition will, of course, occur at the time fixed by adjustn'ient of the timer lever, and the second one should occur between that time and the time when the expansion stroke of the piston begins in the associated cylinder. The first arc across the points of the spark plug will, of course, be equal in intensity to that of any ordinaryigniter employing a circuit breaker of the general type herein disclosed. Therefore, any added effect obtained by the second are necessarily adds to the development of power by accelerating combustion in the cylinder.

In Figure 2, I have illustrated a modified form of circuit breaker. It Will be understood that the circuits will be the same as illustrated in Figure 1. The circuit breaking lever 6 carries but one actuating arm 20, but the timer cam is provided with two actuating projections 30 and 31 at each angle of the hexagon. These projections and 31 are so spaced as to eause'a separation of the contact points 7 and 8 Within the same time interval as in Figure 1, and the depression 32 between the projections 80 and 31 receives the actuating arm 20 and allows the primary circuit to be closed for the brief interval required to allow the initial secondary wave to subside. the condenser to discharge, and full current flow both forms of construction the circuit breaking operations occur in pairs, the interval between those of any given pair beingextreinely short as compared with the intervals between the pairs. The rotary movement of the actuator cam will of course be continuous.

I claim:

1. In an electric ignition system for inter-' nal combustion engines, the combination with a timer cam, of a circuit breaking lever having a pair of actuating arms adapted for successive contact with a single cam projectionduring the eilective ignition period of an associated engine cylinder, said cam projection and arms being arranged to allow the circuit breaking lever to move to circuit closing po-' sition while the cam projection is passing from one of said arms to the next.

2. In an electric ignition system for internal combustion engines, the combination With a timer cam, of a circuit breaking lever provided with a block of insulating material having a pair of arms of unequal length for contact with said cam, said arms being inclined in the direction from which the cam surfaces approach, and the relative length and proximity of the arms being such that radial projections on the cam will actuate them successively to move the lever to circuit breaking position twice during the effective ignition period of a single associated cylinder.

3. In an electric ignition system for internal combustion engines, the combination with a timer cam, of a circuit breaking lever having a pair of arms of unequal length composed of insulating material and adapted for suecessive contact With a cam projection during the effective ignition period of an associated engine cylinder.

\VILLIAM (I. ROBE. 

